"I think it will be a tough match because I have watched Rafa play," Davydenko said. "He is playing good tennis at the moment. He can play for 10 hours, I can't. The fans will get to watch a good match."

Nadal and Davydenko have each won four times in head-to-head matches.

"I don't know for how much longer I can hold this level of tennis," Davydenko said.